Which of the following pairs represents isobars?

Match the isotopes in List $I$ with the number of neutrons in List $II$.

$(A)$. $^{24}_{12}Mg$	$(I)$. $5$
$(B)$. $^{27}_{13}Al$	$(II)$. $12$
$(C)$. $^{9}_{4}Be$	$(III)$. $6$
$(D)$. $^{12}_{6}C$	$(IV)$. $14$

Nuclear reactivity of $Na$ and $Na^+$ is same because both have

The total number of neutrons in dipositive zinc ions with mass number $70$ is

The chlorine atom differs from the chloride ion in the number of:

An atom is composed of protons,neutrons,and electrons. If the mass of a neutron is halved and the mass of an electron is doubled,what will be the change in the mass of the nucleus of $_6C^{12}$?